MPO Multi-fiber Push-On connectors are all made in accordance with the international standard IEC61754-7. MPO patch cable wiring must meet the TIA/EIA-568-C.3 standard and after 1000 plug-ins and unplugs, the IL change is ≤0.3dB and the RL change is ≤5dB. Through the above multi-dimensional tests, it can be ensured that the MPO patch cable can stably support 40G/100G transmission in high-density wiring in data centers. The test record should include the end face image, IL/RL data and polarity type to facilitate link fault tracing.
The following will describe each test process and key points in detail, hoping to help customers who want to use MPO patch cords.
Core performance tests
End face geometry parameter detection (3D detection)
Radius of curvature (ROC): It needs to be controlled within 10–25mm. If it is too small, the optical fiber will be damaged by pressure, and if it is too large, an air gap will be generated to affect signal transmission.
Vertex offset: The deviation between the core axis and the highest point of the end face should be ≤50μm. Excessive offset will significantly increase insertion loss and return loss.
Fiber height: The distance between the optical fiber end face and the surface of the ceramic ferrule must be within ±50nm to ensure close physical contact.
Use an end face detector (400x/200x high-definition imaging) to intuitively judge the end face quality and avoid manual focusing errors.
Optical performance test
Insertion loss (IL):
Test method: Connect the two ends of the jumper with an insertion loss meter and record the difference in optical power between the input and output ends.
Standard requirements: Typical value of MPO end ≤0.5dB, branch end (such as LC) ≤0.3dB.
Return loss (RL):
Test method: Observe the reflected light power through the winding method (winding ≥5 turns), and read the value after stabilization.
Standard requirements: Single mode ≥60dB, multimode ≥20dB; APC end face ≥55dB.
Note:
During the test, you need to use the corresponding test adapter, such as FC-LC adapter to measure LC patch cable. Because the connector on the general test instrument is FC interface. Therefore, you need to use an FC-LC adapter like below:
Polarity Verification
MPO jumpers are divided into three polarity types, which need to be confirmed with a special tester:
| Type | Line sequence rule | Key direction | Application scenarios |
| Type A straight-through | 1→1, 12→12 | Key up↔Key down | Rarely used |
| Type B interleaved | 1→12, 12→1 | Key up↔Key up | 40G/100G multimode mainstream |
| Type C in pairs | 1→2, 2→1 (adjacent fiber cores cross) | Key up↔Key down | Specific duplex links |
Test method:
Connect the MPO jumper to the MPO polarity tester, select the corresponding mode (automatic/full light/manual), and the light source lights up the fiber cores in sequence. Determine whether the polarity is correct by the line sequence lighting sequence or alarm prompt.
Test equipment and process
Benchmark calibration: Connect the light source and optical power meter with a male-male patch cable, and scan and save the reference value after warming up for 15 minutes.
| Insertion loss & return loss tester | MPO polarity tester |
| Measure the IL and RL of MPO connectors | Test the polarity of 8-core, 12-core, 16-core, 24-core fiber connectors A B C. |
| End face detector | Visual fault locator |
| Detect the polishing accuracy and cleanliness of MT end faces. | Basic connectivity check, and confirm if the fiber is broken or not |
Yingda will test all the MPO patch cables in standardized process like below:
Compatibility and adaptability notes:
Testing 12 fiber or 24 fiber MPO patch cables requires an MPO tester with matching channels.
The operating wavelength of multimode patch cords is 850/1300nm, and that of singlemode patch cords is 1310/1550nm. The instrument wavelength must correspond.
Common causes of failure:
- The end face is contaminated or scratched, so it needs to be cleaned before testing.
- Polarity error, Type B polarity reverse connection causes communication interruption.
- Bending radius of patch cord is less than 30mm, and the additional attenuation of the optical cable exceeds 0.2dB/km.
FAQ
How to clean the end face of MPO fiber patch cord?
MPO fiber patch cord requires a special MPO connector. 8 Fiber and 12 fiber MPO fiber cleaner pens are common, and 16 fiber MPO connector also has a special fiber cleaner pen. Specific reference is as follows:
8F 12F MPO cleaner pen
16F MPO cleaner pen
What equipment is needed to test MPO fiber patch cords?
MPO fiber patch cord testing requires an insertion loss meter, MPO polarity tester, end face detector and red light pen.
What is the life of an MPO fiber patch cord?
The patch cord of an MPO fiber connector is limited by the MPO fiber connector, and the life of an MPO connector is generally 500 times. If a high-precision MTP connector is used, it can be used for more than 600 times.
